Torsion springs are presently designed in z-acceleration sensors and xz-acceleration sensors (as a rotatable rocker) either having a simple beam, a length and a width being used as a degree of design freedom, or as a conductor spring (two longitudinal beams connected by cross beams) if, in addition to the usual requirements (requirements relating to detection sensitivity, etc.) vibration requirements must also be met.
In the case of a simple beam, the required use mode (detection mode) is adjusted by a length and a width, which means that positions of other modes are predefined. Thus, shifting the interference mode without shifting the use mode and vice versa is virtually impossible.
A present approach to this problem is to use very short and very thin micromechanical springs, which inevitably results in a wide production variation (strongly dependent on an edge loss, i.e., deviations of actually produced dimensions as opposed to planned dimensions due to production tolerances).
U.S. Patent Application Publication No. 2008/0141774 A1 describes an acceleration sensor, which is sensitive in one direction, measurements being virtually undistorted due to interference accelerations acting perpendicular to this direction. For this purpose, springs of the acceleration sensor have two bending beams, which are connected by cross beams.
German Patent Application No. DE 10 2006 051 329 A1 describes a z-accelerator sensor based on the rocker principle, which has a reduced interference sensitivity as a result of design-related errant deflections. For this purpose, a multiple arrangement of multiple torsion springs extending in parallel is described, as a result of which a flexural stiffness of the arrangement is increased significantly as compared to the flexural stiffness of one individual spring.
U.S. Patent Application Publication No. 2014/0331770 A1 describes a mechanical connection, which forms a pivotal point for MEMS mechanical structures and NEMS mechanical structures.
U.S. Patent Application Publication No. 2013/0192362 A1 describes a vibration-tolerant acceleration sensor structure.